Single channel secrecy device



March 19, 1946.

J. A. SPENCER SINGLE CHANNEL SECRECY DEVICE 2 Sheets-Sheet 1 Filed March15, I943 INVENTOR Jcbvzasfl..djbencer ATTORNEY March 19, 1946; J. A.SPENCER 2,397,053

SINGLE CHANNEL SECRECY DEVICE Filed March 15, 1943 2 Sheets-Sheet 2NORMAL Q; F 7

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INVENTOR James/I pjvelzfier avygg Patented Mar. 19, 1946 UNITE STATESOFFHQ SINGLE CHANNEL SECBECY DEVICE James A. Spencer, Teaneck. N. J.,assignor to Radio Corporation of America, a corporation of Delaware 8Claims.

This invention relates to secrecy system for telegraph communication,either wire or radio.

In my co-pending application filed March 5, 1943, Serial No. 478,065, Ihave disclosed a secrecy system applied to multi-channel circuits, inwhich the tape transmitter and the printer for one channel are operatedduring the time assigned to another channel. In single channel systems,special provision must be made for storing some of the signal unitswhile the tape transmitter and pritner are being operated; otherwise,the full channel time cannot be utilized for transmission of thesignals. Such a system is disclosed, for example, in my co-pendingapplication filed September 17, 1940, Serial No. 357,109,

now Patent No. 2,327,075, granted August 17,

1943, and I have disclosed my present improvement in combinationtherewith.

It is an object of this invention to provide a secrecy device operatingat random, with provisions for storing units of a code character whilethe tape transmitter and receiving printer are being operated.

Another object of the invention is to provide a random signal reverserfor a single channel printing circuit utilizing storage means to permitsignaling during the entire channel time.

Another object of the invention is to provide a phasing device for asecrecy system automatically operable by means of a prearranged code.

Another object of the invention is to provide tape-operated devices forrandom reversing of the signals cooperating with signal storing means.so that full channel time may be utilized for si nal transmission andrecording.

Other objects will appear in the following specification, referencebeing had to the drawings, in which:

Figure l diagrammatically illustrates the transmission circuits of myinvention.

Figure 2 is a schematic illustration of the tape transmitter.

Figure 3 diagrammatically illustrates the circuits of my invention atthe printing or recording station.

Figure 4 shows a seven unit code diagram.

Referring to Fig. 1, reference character it! represents generally thesignal distributor having solid and segmented rings, While l I indicatesgenerally a similar distributor for performing the local functions ofthe station, which in this case is the operation of tape transmitters inFig. 2.

The tape transmitter has an operating magnet [3 with a pivoted armatureHi. When moved downwards a certain distance, this armature engages alever l6 pivoted at IT and moves ratchet bar l8 upwards, which causesthe pivoted dog l9 to engage and move the ratchet wheel 20 secured to apinwheel 2|. The pins of this wheel engage the driving holes in theperforated tape 22 and step it forward one code unit each time thearmature I5 is moved by energization of magnet l3. Spring-pressed rollercatch Zla holds this movement. Armature l5 also operates the seeker bars24 through an extension 23, one seeker bar only being visible in Fig. 2.Since I have chosen to illustrate my invention in a seven unit codesytem, there are seven of these bars closely spaced to position theround pins 25 against the tape, under pressure of spring 26 op eratingthrough levers 21. Each of the seven seeker bars has its own elevatinglever 27 and spring 26, so that they are pressed independently againstthe tape. Each seeker bar also has 2. lug 28 engaging its switch lever29, which moves the cooperating tongue '1 against either a markingcontact M or a spacing contact S under action of spring 3!], dependingupon the position of the seeker bars. There are, of course, seven ofthese tongues and they are designated as T1, T2, T3, T4, T5, T6 and T7in Fig. 1.

Since provision must be made for stopping and starting the tapetransmitter from time to time, special means are provided for thispurpose. This consists of a thumb lever 3i pivoted at 32, on which isalso independently pivoted a lock arm 33. Supring 34 has one endfastened to lever B! and the other end fastened to lock arm 33. Thespring, when on one side of the center, as shown in Fig. 2, positionsthumb lever 3| and lock arm 33 against stop pins 35 and 36,respectively.

When the thumb lever 3| is moved clockwise against stop 36', the spring3G passes dead center and snaps the lever 33 against stop 31, if themagnet l3 happens to be energized at the time. In such position the slot33 in look arm 33 passes over the hooked extension 39 of the armatureHi. When the magnet is de-energized, the hook slips under the slot wall.This looks both the armature and arm 33. However, if the magnet l3 doesno happen to be energized when thumb lever 35 is moved as described, thelock arm 33 snaps against the end of extension 39. When the magnet I3 isnext energized and the armature is attracted, the lock arm moves againststop pin 3! with the same result. When thumb lever 3i is moved clockwiseto unlock the armature, the armature cannot release until the magnet E3is next energized and the hook pulled slightly to the left in Fig. 2.Thus, the transmitter is locked and unlocked at a definite time in thecode cycle, as will be later explained in detail.

In the locked position of the transmitter, the switch blade ie engagesthe contact 4|, which places positive potential onconductor 42 connectedto relay R1 (Fig. 1).

Since the tape transmitter is a prior art structure, it has been shownin somewhat diagrammatic form, so that its method of operation will bemore quickly grasped.

Referring now to Fig. l, the usual message transmitter A is showndiagrammatically, but its construction is like that shown in Fig. 2. Thetongues T1, T3 and T4 of this message tape transmitter are connecteddirectly to the segments Nos. 1, 3 and 4 of the distributor is, buttongue T2 is connected to segment No. 2 of this distributor throughtongue d3 of relay R1 and its cooperating break contact. This relay alsohas two additional tongues 45 and 46 engaging break contacts connectedto the negative terminal through contacts of another relay, to be laterreferredito. The make contacts of this relay are all connected to themark bus bar of the first four contacts of tranmitter A. Tongue T5 isconnected to one terminal f the coil of storing relay 41, the otherterminal of this coil being connected to ground through tongue Q8 ofrelay 49 and its cooperating make contact. Tongue Ts of'the tapetransmitter is connected to one terminal of the'coil of storing relay58, the other terminal of which is connected to ground through tongue ofrelay 49 and the cooperating make contact. Tongue T1 of the tapetransmitter is connected to one terminal of the coil of storingrelay'52'. the other 3 terminal of which is connected'to ground throughthe tongue of relay 49 and the associated make contact.

Relays ll, 5! and 52 have holding coils connected to the positiveterminal through their make contacts 53, 54 and 55, respectively. Theother terminals of these coils are connected to ground through breakcontacts 60 of relay 6|. The remaining make and break contactsassociated with the tongues of relays 41, 55] and 52 are connectedrespectively to positive and negative potential.

Segments Nos. 5 and '7 of distributor are not joined to tongues T5 andT7, but are connected to tongues 55 and 58 of relays 47 and 52,respectively, through tongues 45 and 46 of relay R1. Segment No.6 is notconnected to tongue Ts, but to tongue 51 of relay 59.

Referring now to distributor H, segments Nos. 1 and 2 are connected toground through the coils of-relays 6! and 59, respectively. Segment No.3 is preferably connected to segment No. 2 to increase the length oftime available for energization of the coil of relay 4%, but this is nota requirement. Segment No. 5 is connected to ground through the coil ofthe operating magnet l3 of the tape transmitter A. Segment N0. 6 isconnected to ground through the coil of the operating magnet 62 of thetransmitter B. Tape transmitter B has the same general construction asshown in Fig. 2 and is used to reverse the first four signal units atrandon for secrecy purposes, as later explained in detail. The functionof the relays 4?, 5i! and 52 is to store the fifth, sixth and seventhsignal units so that they will not be destroyed when the tape isadvanced to a new position upon the brushes reaching segment No. 5.

The markcontacts on tape transmitter A are connected difierently fromthe transmitter in my said co-pending application, Serial No. 357,103,

aseiose so as to provide for random signal reversals by transmitter B.Mark contacts Nos. 1, 2, 3 and 4 are connected to the tongue 6% of relayR2, while mark contacts Nos. 5, 6 and 7 are connected to the positiveterminal. The space contacts Nos. 1, 2, 3 and 4 are connected to thetongue 65 of this relay, but space contacts Nos. 5, 6 and '7 are blank,as in my last-mentioned co-pending application. The break and makecontacts cooperating with tongues 54 and 65, respectively, are connectedto the negative terminal, While the make and break contacts respectivelyengaging such tongues are connected to the positive terminal. The coilof relay R2 is shown connected between ground and the tongue T'1 oftransmitter B, but it may be connected to T'2, T's or T'i.

The mark contacts of transmitter B are connected to the positiveterminal. Contacts engaging tongues Ti, T2, T's and T4 are connected tothe negative terminal and the other space contacts are left blank.

Brushes 68 and 69 are mechanically connected together or otherwisearranged to rotate at the same speed and in the same phase over thesolid and segmented rings of distributors It and H, respectively. Thesebrushes connect segments Nos. 1 to '7 to their solid rings, as will beunderstood. The solid ring of distributor H is connected to positivepotential and the solid ring of distributor H3 is connected to oneoutgoing line iii, the other outgoing line "ii being grounded. Theselines may connect to suitable radio transmitting devices for radio usesor they may be connected to devices for wire transmission, as myinvention is applicable for either use.

Referring to Fig. 3, the incoming signals are received over lines l2,73, which may be understood to come either from a radio or a wirestation, as previously indicated, and for purposes of explanation it maybe assumed that the signals in these wires are plus and minus pulsescorresponding to the plus and minus pulses sent out over thetransmission wires '50 and H. The incoming wires are connected to thecoil of polar line relay 14, having one of its contacts connected to thepositive terminal and the other one connected to ground, which is theplus and minus terminal. The tongue of relay Hi is connected to thesolid ring of distributor F5. The solid ring of local functiondistributor 16 is connected to positive potential and brushes l1, 78 aremechanically joined or are otherwise made to rotate together and theyalso rotate in synchronism and phase with the brushes at thetransmitting station, by

means well known in the art, not shown.

Segment No. 1 of distributor i5 is connected through the operating coilof relay 19 to the conductor 83, which relay hasa tongue 8E3 closingthrough its make contact a holding circuit for the relay. This holdingcircuit may be traced from positive potential through the holding coiland the break contacts of relay iii to the ground terminal. Relay 5'9has a tongue 82 connected to one terminal of the No. l printer selectormagnet,

the other terminal of which is connected to conductor 83. The printermagnets are indicated as a whole by reference character PM. The makecontact cooperating with tongue 82 is connected to the fourth segment ofthe looalfunction distributor 76. No. 2 segment on distributor isconnected to tongue 84 of a multi-contact phasing switch 85. The makecontact cooperating with this tongue is connected to ground through theoperating coil of. relay 86. Switch tongue 8! of this relay engages'itsmake contact when the opcrating coil is energized. and closes thecircuit through its: holding coil from the positive terminal to thebreak switch of relay 81. This relay has a second tongue 88 adapted toengage its make: contact to close the circuit from the fourth segment ofdistributor 16 through No. 2 printing magnet to the conductor 83.

No. 3 contact of distributor I5 is connected to one terminal of theoperating coil of relay 89, the other terminal being connected toconductor 83. This relay has a tongue 93 adapted to engage a makecontact, which closes the circuit from the positive terminal through aholding coil through the break switch of relay BI The relay 89 also hasanother tongue 9i adapted to engage its make contact and close thecircuit from the fourth segment of distributor 16 through the No. 3printing magnet to the common conductor 83. The

fourth segment of distributor I5 is connected through the fourthprinting magnet to the conductor 83.

The common conductor 83 connected to the first, second, third and fourthprinting magnets PM. is connected to the tongue of polarized relay 92.The mark contact M of this relay is connected to the positive terminaland the space contact S is connected to ground.

The fifth segment of distributor E5 is connected to switch tongue 93 ofphasing switch 85 and the make contact cooperating with this tongue isconnected through the fifth printing magnet to ground. No. 6 segment ofdistributor is connected through the sixth printing magnet to ground.The seventh segment of distributor 15 is connected to tongue 94 ofphasing switch 85 and the make contact cooperating therewith isconnected through the seventh printing magnet to ground. The eighthpulse printing magnet is connected between the seventh segment ofdistributor l6 and ground.

The operating coil of relay 52 is shown connected to tongue T1 of adecoding or reversing tape transmitter C, but it may be connected to T2,T: or T"4, and it must have the same adjustment as tape transmitter B atthe transmitting station. The mark contacts M of tape transmitter C areall connected to the positive terminal and the space contacts Scooperating with tongues T"1, T"2, T"3 and T"4 are all joined to thenegative terminal. The other space contacts and tongues T5, T"s and T"7take no part in the operation and are blank.

The coil of the operating magnet 96 of tape transmitter C' has oneterminal connected to ground and the other one connected to the breakcontact cooperating with tongue 91 of phasing relay 85. The breakcontacts cooperating with tongue 84, 93 and 94 are connected to a pointintermediate between the negative terminal and ground through the coilsof polar relays 98, 99 and I00, respectively. The reason for thisintermediate tap is to cause positive and negative current flow when thetongue of relay M is on the plus and ground contacts, respectively.These three relays, as well as the other polar relays, are designed sothat their tongues remain on a contact until thrown in the oppositedirection by current of the opposite polarity. When energized withpositive current, the relays 98, 99 and I00 engage their lower contactsand apply positive potential to the tongue 91 of phasing switch 85through the switch tongues I0 I, 102, I03 of these relays in series.When energized by negative current, they move against their blank uppercontacts.

The break contact cooperating with tongues 91 of phasing switch isconnected to the sixth segment of local function distributor It, so thatpotential is applied to the operating magnet 96 of tape transmitter 0both by the No. 6 segment and by the phasing switch, as will later beexplained in detail. The transmitter C has the general constructionshown in Fig. 2, but neither it nor transmitter B has any connectionsextending from the switch contacts 40, 41. These are utilized only inthe transmitter A.

The operation of my invention will now be described:

Before regular transmission of messages can begin, it is necessary tophase the B and C transmitters so that they have the perforations of thesame code characters over'the seeker pins at the" same time. All threetransmitters are manually looked, as described in connection with Fig.2. The message tape is placed in the A tape transmitter and continuousbelts of identically perforated tape will be placed in the B and Ctransmitters. o perform the phasing operation, the B and C tapes areplaced in position so that they have the same character in position overthe seeker pins, which character has a perforation in the position inwhich a tongue is connected to' relays R2 and 92, respectively. As shownin Fig. 1, this would mean a perforation in the first code unit. Byreferring to the code diagram of Fig. 4, it will be seen that the B andC transmitters may have in starting position either the letter A, C, D,F, M, O, T! U, W, Y or Z. Suppose, for example, that the B and C tapesare set with the perforations of the letter Z over the seeker pins. Thelocking of the A tape transmitter on space closes switch 40-41 (Fig. 2)and energizes relay R1. The three tongues of this relay then swing fromthe break contacts to the make contacts. This places positive potentialon segments Nos. 2, 5 and '7 through the contacts of relay R2. Lockingof the B tape transmitter on space de-energizes rela R2 and the lockingof the C transmitter on space at the receiver places negative currentthrough relay 92, which moves its tongue on the ground contact.

As the brushes rotate over the segments of the distributors, positivesignal pulses go out over the lines 10, H in positions 2, 5 and I of thedistributor time cycle and negative pulses through tongue 65 in timepositions I, 3 and 4. Negative pulses also go out in position 6 throughthe back contacts of relay 50. This is the idle time signal for theusual seven unit code, as disclosed in my said patent. These idle timesignals are used for phasing the B and C transmitters, as will now beexplained.

To accomplish the phasing, the receiving operator will throw the phasingswitch 85 from normal to phasing in Fig. 3. The idle time signals nowenergize the polar relays 98, 99 and I00 with the mark pulses and theirtongues connect the magnet 96 of the C transmitter to positive potentialthrough tongue 91 of the phasing switch 85. The C transmitter is nowlocked electromagnetically b its operating magnet 62 (being identicalwith magnet l3 of Fig, 2) and its manual 100k 34 is thrown clockwiseagainst pin 35 (Fig. 2). Since the operating magnet is energized, thelooking arm 33 moves free of the hooked end 39 and against pin 36.

The selector relays and the printing magnet are not operated by theseidle time signals, as ground potential appears at both terminals of thecoils in time positions I, 3, 4 and 6 and current is v of the Ctransmitter.

shunted through the phasing circuit in time positions 2, 5 and I.

The transmitting operator then releases at an time thereafter the manuallock on the B transmitter, but not the one on the Atransmitter. The Btransmitter remains locked'because hooked end 353 prevents the lever 33from moving. When segment No. 6 is reached, magnet 62 is energized and.the hooked end moves slightly, which permits the lever 33 to move torelease position against p n Ton ue Ti now is positive by engaging itsmark contact and relay R2 is energized. This reverses the first foursignal units and when segment No. 2 is reached by the brushes, negativecurrent in relay 98 opens the circuit of magnet 96 ofthe C transmitterand it unlocks. The B and C tapes are now properly phased. When thebrushes reach segments 'Nos. 5 and 6 in succeeding cycles, magnets 96and 62 of the C and B transmitters, respectively, are energized and thetapes are thereafter advanced in unison.

The receiving operator now snaps the phasing switch to normal and thetransmitting operator releases the manual lock on the A transmitter antime thereafter, which deenergizes relay R1 and the segments Nos. 2, 5and 7 of distributor l0 are connected to their normal message circuits.

It will be seen that whenever relay R2 is energized, positive currentwill be transmitted on space for the first four code units and negativecurrent on mark. That is, the signals will be reversed in the first fourpositions, but not in the fifth, sixth and seventh positions; but whenrela R2 is de-energized, positive current will be sent out on mark andnegative current on space in the first four time positions, the otherpositions being normal as before, This will be normal transmission withno reversal of the signals.

By an inspection of the B transmitter, as shown in Fig. 1, and referringto the-code in Fig, 4, it will be seen that the relay R2 will beenergized and the signals reversed when the perforations of the lettersA, C, D, F, u i T, U, W, Y and Z are in position over the seeker pins ofthe B transmitter and not reversed when the perforations of the otherletters of the alphabet are in position thereover. Since the Ctransmitter is identical and in phase with the B transmitter, aninspection of the circuits completed by the C transmitter and the relay92 will show that the reversed signals sent out by the transmittingstation will again be reversed, or righted, andnormal printing willoccur; With the perforations of the other letters of the alphabetappearing over the seeker pins in the C transmitter, the rela $2 will beoperated in the opposite direction and the normal signals sent out bythe transmitting station will operate the printing magnets in a normalmanner.

7 Thus, the first four code unit pulses sent out by the A transmitterare scrambled at random by'the continuous belt of tape in the B transmitter, but the signals are correctly printed or otherwise recorded at thereceiver, due to the action An unauthorized receiver, however, will notbe able to translate the garbled transmission.

A description of the action of the storing relays 51, 53 and 52 at thetransmitter and it, 85 and 89 at the receiver need not be given indetail,

as the action is the same as set forth in my said co-pendingapplication, except as modified by my present improvement, Which hasbeen fully described.

The operation of the system when the coils of relays R2 and 92 of the Band C transmitters are adjusted to connect with other than the firsttongues will be apparent without'description.

'It will be apparent that the perforations in the scrambling andunscrambling tapes may be made in accordance with any predeterminedorder of characters, as in a word or. series of words, or even afanciful arrangement of perforations of any sort may be used.

Various. modifications may be made in the improvement Without departingfrom the spirit of the invention.

Having described my invention, what I claim is:

1. In secrecy devices for multi-unit equal length code signal systems, atransmission circuit, a message and a scrambling tape transmitter havinga tacts.

2. In secrecy devices for multi-um't equal length code signal systems, atransmission circuit, a message and a scrambling tape transmitter havinga plurality of pairs of juxtaposed contacts and movable switch tonguesadapted to separately engage P the contacts of said pairs, means forconnecting the switch tongues of the message transmitter successively tosaid transmission circuit, a reversing switch for reversing the polarityof the contacts of said message transmitter, electromagnetic meansconnected to a switch tongue of the scrambling transmitter forcontrolling said reversing switch by the engagement of said tongue witha predetermined one of said contacts, means for shifting the connectionof said means from one tongue to another and means for advancing thetape of the scrambling transmitter once each code character cycle.

3. In a multi-unit single channel system, a message and a scramblingtape transmitter, each having a plurality of pairs of'juxtaposedcontacts and movable switch tongues adapted to separately engage thecontacts of said pairs, means for advancing the tape of the message tapetransmitter before the last units of the code cycle are transmitted,means for storing the said last units before the said tape is thusadvanced, a reversing switch connecting potential terminals to thecontacts that produce the unstored signal units of the messagetransmitter and means controlled by the engagement of'one tongue of thescrambling tape transmitter with one of said contacts for operating saidreversing switch.

4. In a multi-unit single channel system, a message, a scrambling and areceiving tape transmitter having a plurality of pairs of juxtaposedcontacts and movable switch tongues adapted to separately engage thecontacts of said pairs, means for advancing the tapes of saidtransmitters once each cycle, means for storing the signal units set upby the message tape for transmission after the tape is thus advanced,means including a reversing switch for connecting potential to thecontacts that produce the unstored signal units of the messagetransmittena coil for said reversing switch adapted when energized toreverse the potentials applied to the said contacts and means forconnecting said coil to one of the tongues of the scrambling transmitterfor energization on its engaging a mark contact.

5. In a multi-unit single channel system, a message, a scrambling and areceiving tape transmitter having a plurality of pairs of juxtaposedcontacts and movable switch tongues adapted to separately engage thecontacts of said pairs, means for advancing the tapes of saidtransmitters once each cycle, means including a reversing switch forconnecting potential to contacts of the message transmitter, a coiladapted when energized to operate said switch and reverse the potentials applied to the said contacts, means for connecting said coil toa selected tongue of the scrambling transmitter for energization uponits engaging a mark contact, means for locking said transmitters ontheir space contacts and releasing them at a predetermined time in thecode cycle, means for sending predetermined signals when the message andscrambling transmitters are thus locked and auxiliary means operated bysaid predetermined signals for locking the receiving tape transmitterand for releasing the same after the unlocking of the scramblingtransmitter and upon the engagement of said selected tongue with a markcontact.

6. In a multi-unit single channel system, a message, a scrambling and areceiving tape transmitter having a plurality of pairs of juxtaposedcontacts and movable switch tongues adapted to separately engage thecontacts of said pairs, means for advancing the tapes of saidtransmitters once each cycle, means for storing the signal units set upby the message tape for transmission after the tape is thus advanced,means including a reversing switch for connecting potential to thecontacts that produce the unstored signal units of the messagetransmitter, a coil adapted when energized to operate said switch andreverse the potentials applied to the said contacts, means forconnecting said coil to a selected tongue of the scrambling transmitterfor energization upon its engaging a mark contact, means for lockingsaid transmitters on their space contacts and releasing them at apredetermined time in the code cycle, means for sending predeterminedsignals when the message and scrambling transmitters are thus locked andauxiliary means operated by said predetermined signals for locking thereceiving tape transmitter and for releasing the same after theunlocking of the scrambling transmitter and upon the engagement of saidselected tongue with a mark contact.

'7. In a multi-unit single channel system, a message, a scrambling and areceiving tape transmitter having a plurality of pairs of juxtaposedcontacts and movable switch tongues adapted to separately engage thecontacts of said pairs, means for advancing the tapes of saidtransmitters once each cycle, means including a reversing switch forconnecting potential to contacts of the message transmitter, a coiladapted when energized to operate said switch and reverse the potentialsapplied to the said contacts, means for connecting said coil to aselected tongue of the scrambling transmitter for energization upon itsengaging a mark contact, means for locking said transmitters on theirspace contacts and releasing them at a predetermined time in the codecycle, means for sending predetermined signals when the message andscrambling transmitters are thus locked, auxiliary means operated bysaid predetermined signals for locking the receiving tape transmitterand for releasing the same after the ugnlocking of the scramblingtransmitter and. upon the engagement of said selected tongue with a markcontact and means controlled by the receiving transmitter for reversingthe received signals as a selected one of its tongues moves from onecontact to another.

8. In a multi-unit single channel system, a message, a scrambling and areceiving tape transmitter having a plurality of pairs of juxtaposedcontacts and movable switch tongues adapted to separately engage thecontacts of said pairs, means for advancing the tapes of saidtransmitters once each cycle, means for storing the signal units set upby the message tape for transmission after the tape is thus advanced,means including a reversing switch for connecting potential to thecontacts that produce the unstored signal units of the messagetransmitter, a coil adapted when energized to operate said switch andreverse the potentials applied to the said contacts, means forconnecting said coil to a selected tongue of the scrambling transmitterfor energization upon its

